In the Literature: Research You Need to Know

Clinical question: What is the prevalence of silent pulmonary embolism (PE) in patients with deep venous thrombosis (DVT)?

Background: Pulmonary embolism was undiagnosed or unsuspected in approximately 80% to 93% patients antemortem who were found to have a PE at autopsy. The extent to which silent pulmonary embolism explains the undiagnosed or unsuspected pulmonary emboli at autopsy is not certain. Prior studies have demonstrated the association of silent PE in living patients with DVT.

Study design: Systematic review.

Setting: Published trials performed worldwide.

Synopsis: A systematic review of published trials addressing the prevalence of silent pulmonary embolism in patients with deep vein thrombosis was performed. Studies were included if methods of diagnosis of PE were described, if it was an asymptomatic PE, and if raw data were presented. Twenty-eight studies were identified and were stratified according to how the PE was diagnosed (Tier 1: high-probability VQ scan based on PIOPED criteria, CTA, angiography; Tier 2: VQ scans based on non-PIOPED criteria).

Among Tier 1 studies, silent PE was detected among 27% of patients with DVT. Among Tier 2 studies, silent PE was detected among 37% of patients with DVT. Combined, silent PE was diagnosed in 1,665 of 5,233 patients (32%) with DVT. Further analysis showed that the prevalence of silent PE in patients with proximal DVT was higher in those with distal DVT, and that there was a trend toward increased prevalence of silent PE with increased age.

A limitation of this study includes the heterogeneity in the methods used for diagnosis of silent pulmonary embolism.

Bottom line: Silent pulmonary embolism occurs in one-third of patients with deep venous thrombosis, and routine screening should be considered.

Citation: Stein P, Matta F, Musani MH, Diaczok B. Silent pulmonary embolism in patients with deep venous thrombosis: a systematic review. Am J Med. 2010;123(5):426-431.

Reviewed for TH eWire by Alexander R. Carbo, MD, SFHM, Lauren Doctoroff, MD, John Fani Srour, MD, Matthew Hill, MD, Nancy Torres-Finnerty, MD, FHM, Anita Vanka, MD, Hospital Medicine Program, Beth Israel Deaconess Medical Center.

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